升温过程中FRP筋与钢筋力学性能的试验研究

An Experimental Study of the Mechanical Properties of Fibre Reinforced Polymer (FRP) and Steel Reinforcing Bars at Elevated Temperatures

论述了一项（用于混凝土内部增强）FRP筋在升温过程中力学性能的试验研究结果。被研究的FRP筋有两类：直径9．5mm的碳纤维（CFRP）筋和直径9．5、12．7mm的玻璃纤维（GFRP）筋。为了对比，也对普通的10mm和15mm的钢筋进行测试。试验研究结果表明：FRP筋的应力一应变关系在温度上升时几乎保持线性直到失效。然而，在升温过程中，FRP筋的破坏强度呈现总体降低趋势，在500℃时几乎以线性速率达到零。300-400℃时FRP筋的弹性模量基本保持不变，在此温度之后，弹性模量将有一个急速下降。这些特性在输入计算机后可以用来模拟FRP筋混凝土结构的耐火特性。

This paper presents the results of an experimental study of the mechanical properties of FRP reinforcement bars, used as internal reinforcement in concrete structures, at elevated temperatures. Two types of FRP bars namely： carbon fibre reinforced polyester （CFRP） bars of 9.5 mm diameter and glass fibre reinforced polyester （GFRP） bars of 9.5 mm and 12.7 mm diameter were used in the study. For comparison, conventional steel reinforcement bars of 10 mm and 15 mm diameter were also tested. Results from the experimental study show that the stress-strain relationships of FRP bars remained almost linear at elevated temperatures until failure. However, there was a gradual reduction in the failure strength of FRP bars at elevated temperatures, at an almost linear rate to zero at about 500℃. Their elastic modulus remained almost unchanged until 300-400 ℃. After this temperature, there was a sharp drop in the elastic modulus. These properties can be used as input in computer programs for modelling the fire behaviour of concrete structural members reinforced with FRP bars.